Answer:
A. 3/16
Explanation:
The four possible outcomes for Stem length are:
Tt, tT, TT and tt.
The dominant trait (tall stems) will manifest itself in 3 out of 4 outcomes, so its ratio is 3/4.
The four possible outcomes for flower coloration are:
Rr, rR, RR and rr.
The non-dominant trait (white flowers) will manifest itself in 1 out of 4 outcomes, so its ratio is 1/4.
Multiplying both ratios gives us the ratio of offspring that have tall stems and white flowers:
Therefore, the answer is A. 3/16